Question

14) According to the law of reflection, a light ray striking a mirror at an angle of incidence of 30 degrees will leaves the miror at an angle of a. 60 degrees b. 30 degrees c. less than 30 degrees d. none of the above 15) A light ray bends when it goes from one medium to another because of a. interference b. diffraction c. specular reflection d. refraction c. polarization 16) Rank the following media in order according to the speed of light in them, from slowest o fastest: vacuum, air, water and glass. a. air, water, glass, vacuum b. glass, air, water, vacuum c. water, glass, air, vacuum d. glass, water, air, vacuum front of the film. The distance in front of the lens that a screen must be placed for an image to be in focus is 17) A movie projector is equipped with a 0.5 m focal length lens that is positioned 0.505 m in a. 0.5 m b. 0.505 m c. 50.5 m d. 500 m e. 505 m 18) The energy used by a 100 watt light bulb in 1 hour is a. 0.01J b. 360,000.J c. 100J d. 6,000 J none of the above e.

Answer 1

14. Angle of incidence = Angle of reflection

Hence Answer = (b) 30 degree

15. (D) Refraction

16. (D) Glass, Water, Air, Vacuum

17. 1/v = 1/0.5 - 1/0.505 = 0.0198

v = 50.5m (C)

18. Power = 100W

Time = 1 hour = 3600 sec

Energy = Power * Time

=100W * 3600 sec = 360000 J (b)